Modular clip assembly for heat shrinkable material

ABSTRACT

A modular, reusable installation tool for clamping laid-together portions of cross-linked, dimensionally heat unstable polymeric material along a to-be-formed bond line during the application of heat from an external source to form a bond between clamped portions of the material. The tool comprises an assembly of hand-operated clip modules which are threaded longitudinally on a cable to facilitate their rapid one-hand installation and removal along a bond line. An improved modular clip is disclosed which incorporates a pair of bond line gripping flanges attached to a pair of ventilated cooperating jaw plates.

BACKGROUND OF THE INVENTION

I. Field of the Invention:

This invention relates to manually operated clips and similar temporaryclamping devices. More specifically, the invention relates to a reusableinstallation tool formed with a plurality of longitudinallyinterconnected clip modules which is adapted for joining laid-togetherportions of heat recoverable sheet material.

II. Description of the Prior Art:

A wide variety of manually operated spring clamping devices adapted forparticular applications are known in the prior art. The use of such adevice to temporarily clamp laid-together portions of dimensionally heatunstable polymeric sheet material during the application of heat to jointhe clamped portions of the material is believed by applicants to beheretofore unknown. Such a use in conjunction with the formation of awrap-around closure member is disclosed in a concurrently filed U.S.patent application entitled "Method for Forming a Closure Using HeatRecoverable Sheet Material", U.S. Ser. No. 750,976 filed Dec. 15, 1976.This application is assigned to the assignee of the present inventionand is incorporated herein by reference. Of the clamping devices knownin the prior art, none are particularly well adapted for this new use.

One embodiment of the invention relates to improvements in a clipdescribed in U.S. Pat. No. 1,474,102 issued to Leon H. Ashmore on Nov.13, 1923, the disclosure of which is incorporated herein by reference.

SUMMARY OF THE INVENTION

The present invention overcomes many of the disadvantages associatedwith manually operated spring clamping devices known in the prior artwhich could be used for clamping laid-together portions of cross-linkeddimensionally heat unstable polymeric material along a to-be-formed bondline during the application of heat from an external source to form abond between clamped portions of the material. It does so by providing anovel modular clip assembly including at least two clip modules each ofwhich possesses first and second parallel jaws, first and second handlesconnected respectively to the jaws, hinge means for allowing the jaws tomove cooperatively into and out of engagement with each other inlongitudinally parallel relationship, and spring means for urging thejaws into mutual engagement. Flexible linking means interconnecting theat least two clip modules are employed for maintaining a selectedlongitudinal relationship between the modules thereby facilitating thehand installation of the modular clip assembly along the to-be-formedbond line.

In one embodiment, improvements are made to a clip of the type having apair of longitudinally parallel jaws formed with cooperating plates,spring means urging the jaws toward a closed position in which the jawsare in contact with each other, and manually operable means for urgingthe jaws away from the closed position, wherein the improvements includea pair of jaws each possessing a gripping flange disposed inwardly atthe terminal portion of each cooperating plate, each gripping flange andassociated plate having a generally L-shaped cross-sectionalconfiguration, the short arms of the L's which correspond to thegripping flanges being substantially colinear in the closed position,the portions of the plates corresponding to the long arms of the L'sbeing provided with a plurality of ventilating apertures adjacent thegripping flanges.

For specific applications, the parallel jaws of each clip module can beconfigured to conform to that portion of a selected to-be-formed curvedbond line corresponding to the module--s position in the longitudinalassembly.

BRIEF DESCRIPTION OF THE DRAWINGS

The many objects and advantages of the present invention will becomeapparent to those skilled in the art when the following description ofthe best mode contemplated for practicing the invention is read inconjunction with the accompanying drawings, wherein like referencecharacters refer to the same or similar elements, and in which:

FIG. 1 is a perspective view of a sheet of heat-shrinkable polymericmaterial partially installed with the modular clip assembly of theinvention around a substrate;

FIG. 2 is a perspective view of the modular clip assembly of theinvention partially removed from along the clamped and bonded portionsof the sheet;

FIG. 3 is a cross-sectional view of a clip module installed on ato-be-formed bond line along laid-together portions of the sheet as seenthrough the lines 3--3 in FIG. 1;

FIG. 4 is a cross-sectional view through the lines 4--4 in FIG. 1showing adhesives positioned for clamping between laid-together portionsof the sheets;

FIG. 5 is a partial cross-sectional view through the lines 5--5 in FIG.2 which shows a portion of a completed closure member formed around thesubstrate with the clip module removed;

FIG. 6 is a cross-sectional view through the lines 6--6 in FIG. 2 whichshows a portion of the bonded and heat shrunk sheet with a reusable clipmodule still in place;

FIG. 7 is a cross-sectional view through the lines 7--7 in FIG. 2 whichshows the clamped, bonded and heat-shrunk sheet with a bonding adhesivedisposed between the clamped portions;

FIG. 8 is a perspective view of a stylized modular clip assembly of theinvention possessing curved cooperating parallel jaws for forming aselected curved bond line;

FIG. 9 is a perspective view of a presently preferred embodiment of theinvention;

FIG. 10 is an end view of a presently preferred improved modular clipshown with the cooperating parallel jaws in the closed position;

FIG. 11 is a side view of the improved modular clip shown in FIG. 10;

FIG. 12 is an end view of the improved modular clip of FIG. 10 shownwith the cooperating parallel jaws in an open position; and

FIG. 13 is a view looking into the closed jaws of the improved modularclip shown in FIG. 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now generally to the several figures and specifically to FIG.1, a sheet of cross-linked, dimensionally heat-unstable polymericmaterial 10 is shown wrapped partially about an elongated substrate 12.The substrate 12 may comprise for example, a conductor, a pipe, aconnector, or the like. Moreover, the substrate 12 need not be ofconstant cross-section as is shown in FIGS. 1 through 7. The heatinstability of the sheet 10 and its orientation with respect to thesubstrate 12 is preferably such that the sheet is shrinkable around thecircumferance of the substrate and most preferably such that the sheetis shrinkable around the circumferance of the substrate without asubstantial change in length along the longitudinal axis of thesubstrate. A particularly economical sheet with the preferred heatinstability characteristics can be fabricated by simply extruding a tubeand rendering it heat shrinkable by the method of Cook et al., U.S. Pat.No. 3,086,242, the disclosure of which is incorporated herein byreference. A heat recoverable tube so fabricated is then slitlongitudinally to form the desired sheet.

The sheet 10 possesses a pair of primary surfaces 14 and 16 which willfor convenience be referred to as the outside surface and the insidesurface respectively. It is, of course, obvious that the relativepositions of the primary surfaces 14 and 16 can be easily interchangedby wrapping the sheet 10 "inside-out" around the substrate 12. After thesheet 10 is wrapped around the substrate 12, portions of the insidesurface 16 are laid together in contact with one another to form agenerally tubular structure around the substrate 12. The portions of thesheet which are laid together as described and shown are said to bearranged in a lay-up lap seal configuration. This configuration of thesheet 10 is to be distinguished from an overlap seal configurationwherein a portion of the inside surface 16 is juxtaposed with a portionof the outside surface 14 again forming a generally tubular structurewhich surrounds the substrate 12. The importance of using a lay-up lapseal configuration rests in the ability of the protruding laid-togetherportions of the sheet 10 to be clamped on the outside of the resultingtubular structure. It is clear that more complex laid-togetherconfigurations of the sheet 10 involving combinations of a lay-up lapseal and an overlap seal also possess the ability to be clampedexternally.

A modular clip assembly 18 of the invention is shown in FIG. 1 partiallyinstalled on a to-be-formed bond line along laid-together portions ofthe sheet 10. The modular clip assembly 18 includes a plurality ofmanually operable clip modules 20 longitudinally interconnected by aflexible cable 22 which is threaded through each module 20 as shown. Apair of retaining beads 23 disposed at each end of the flexible cable 22confine the individual clip modules 20 on the cable 22. Thus confined,the hand installation of the clip modules 20 is facilitated because thenext module to be installed is always close at hand. Each clip module 20possesses a pair of cooperating parallel jaws 24 which engage and clampthe laid-together portions of the sheet 10 positioned there between. Inmost applications, the parallel jaws 24 of each modular clip 20 arepreferably installed in substantial longitudinal abutment with oneanother to define a substantially continuous to-be-formed bond line.Although FIGS. 1 and 2 show the parallel jaws 24 of the modular clipassembly 18 installed to form a straight bond line, it is to beunderstood that curved, substantially continuous bond lines can also beformed. Curved bond lines are particularly useful for forming closuresaround irregularly shaped substrates, such as, for example, where ato-be-covered substrate changes from a small cross-section at one end toa larger cross-section in the middle and then back to a smallcross-section at the other end. A substantially continuous curved bondline can be formed from straight bond line segments using the modularclip asembly 18 shown in FIGS. 1 and 2. Alternatively, special purposemodular clip assemblies can be fabricated with each module having curvedparallel jaws that conform to the curvature of the underlying substrateat the location corresponding to the module's position in the assembly.Clamping laid-together portions of the sheet 10 with the modular clipassembly 18 forms a tubular assembly 26 which is ready for heating.

An external heat source (not shown) is used to heat portions of thetubular assembly 26 to bond the materials clamped between thecooperating parallel jaws 24 and to shrink selected portions of thesheet 10 radially around the substrate 12. Suitable external heatsources include for example, electric hot air heat guns, open flametorches and infrared electric lamps.

The modular clip assembly 18 can be used to clamp laid-together portionsof cross-linked, dimensionally heat unstable polymeric materials duringthe application of heat to form two broad categories of bonds. The firstcategory of bonds are formed with self-bonding materials that coalescewith one another at their recovery temperature where juxtaposed andclamped. The second category of bonds are formed with separate adhesivematerials sandwiched between the juxtaposed and clamped materials to bebonded. These adhesive materials can be disposed, as shown in FIG. 1, asa layer 28 formed on a portion of the inside surface 16 along at least apart of the to-be-formed bond line sandwiched between the clampedportions of the sheet 10. Alternatively, for example, a strip of hotmelt adhesive, supplied separately in the form of a tape, can beinterposed between the laid-together portions of the sheet 10 along theto-be-formed bond line prior to clamping and heating.

After the tubular assembly 26 has been heated to form the bond line andto shrink selected portions of the sheet 10, the tubular assembly ispreferably allowed to cool to room temperature.

FIG. 2 shows the modular clip assembly 18 of the invention being removedfrom along the bond line 32 of a finished closure member 34 formed withthe sheet 10 about a portion of the elongated substrate 12.

FIG. 3 is a cross-sectional view of the tubular assembly 26 as seenthrough the lines 3--3 in FIG. 1. An individual clip module 20 is shownclamping laid-together portions of the sheet 10 which is formed withself-bonding polymeric materials.

FIG. 4 is a cross-sectional view through the lines 4--4 in FIG. 1 whichillustrates the adhesive layer 28 and the strip of hot melt adhesivetape 30 positioned for clamping between laid-together portions of thesheet 10. When adhesive as shown in FIG. 4 are employed the sheet 10need not be self-bonding.

FIG. 5 is a partial cross-sectional view through the lines 5--5 in FIG.2 which shows a portion of a completed closure member 34 formed aroundthe substrate 12 with the clip module 20 removed. The coalescing ofself-bonding materials is shown stylistically in this view.

FIG. 6 is a cross-sectional view through the lines 6--6 in FIG. 2 whichshows a portion of the bonded and heat shrunk sheet 10 with a clipmodule 20 in place. This view illustrates how the cooperating paralleljaws on the clip module 20 are configured to avoid interference with therecovery of the clamped portions of the sheet 10.

FIG. 7 is a cross-sectional view through the lines 7--7 in FIG. 2illustrating the clamped, bonded and heat-shrunk tubular assembly 26with a stylized adhesive 36 bonding the clamped portions of the sheet10.

The foregoing discussion of FIGS. 1 through 7 has focused on a presentlypreferred use of the modular clip assembly 18 in the formation of awrap-around closure member 34 from a single sheet 10. Nevertheless, itis to be understood that the scope of the invention's utility isbroader. For example, the invention can be used to temporarily clamp,during heat bonding, laid-together edge portions of two smaller sheetsof cross-linked, dimensionally heat-unstable polymeric material to forma larger sheet. Further, the invention can be used with a sheet ofcross-linked, dimensionally heat-unstable polymeric material to form anend closure around a truncated substrate. Such a closure may be formedby positioning the sheet formed in a generally tubular configuration tooverhang the truncated end of the substrate and by extending the bondline normally disposed along the longitudinal axis of the substratearound the truncated end to seal off the overhanging tubular portion.Similarly, the modular clip assembly of the invention can be used toform an end closure cap by forming a bond line at one end of a tubularsection of cross-linked, dimensionally heat-unstable polymeric material.

FIG. 8 is a perspective view of a stylized modular clip assembly 80which best illustrates the structural elements of the invention. A firstmanually operable clip module 82 possesses first and second paralleljaws 84 and 86 respectively. These jaws are connected respectively tofirst and second handles 88 and 90. A hinge means, shown generally at92, allows the jaws 84 and 86 to move cooperatively into and out ofengagement with each other in longitudinally parallel relationship. Aspring means, shown as a coil spring 94, urges the jaws 84 and 86 intoengagement. The assembly includes a second manually operable clip module96 which possesses elements corresponding to those of the first manuallyoperable clip module 82. Flexible linking means, shown as a chain 98,interconnects the first and second clip modules 82 and 96 respectively.The chain 98 functions to maintain the selected longitudinalrelationship shown, thereby facilitating the hand installation of themodular clip assembly 80 along the to-be-formed bond line. Third andfourth manually operable clip modules 100 and 102 respectively, areshown in FIG. 8 to better illustrate the advantages of longitudinallyinterconnecting individual clip modules. Each of the parallel jaw pairson the four modules shown 82, 96, 100 and 102 are specially configuredto conform to a portion of a selected to-be-formed curved bond linecorresponding to the module's position in the longitudinal assembly ofmodules 80. The chain 98 maintains the selected longitudinalrelationship shown between the four modules thereby insuring that theproper jaw pairs are installed at each location along the selectedto-be-formed curved bond line.

FIG. 9 is an uninstalled perspective view of the modular clip assembly18 shown partially installed in FIGS. 1 and 2. Although the modular clipassemblies shown in FIGS. 1, 2, 8 and 9 each are formed with four clipmodules, it is to be understood two or more modules can belongitudinally interconnected to form an assembly of any desired length.

FIGS. 10 through 13 provide four views of a presently preferredembodiment of the clip module 20. Novel improvements have been made in aclip described in the Ashmore Patent (referenced above) to arrive at theclip module shown. The module 20 is formed with a pair of substantiallyidentical plates 104 of generally T-shaped configuration which is bestseen in FIG. 11. Each plate possesses an inside surface 106, an outsidesurface 108, a jaw portion 110 corresponding to the upper horizontalpart of the T and a handle portion 112 corresponding to the verticalpart of the T. A pair of projections 114 on the jaw portion 110 aredisposed parallel to and on opposite sides of the handle portion 112.These projections are cupped on their inside surfaces 106 to formspherical-bearing seats 116. The plates 104 are juxtaposed as shown witha pair of ball bearings 118 disposed between aligned bearing seats 116thereby forming two joints about which the plates 104 may rock. A pairof tubular clamping springs 120 are disposed around the joints to holdthe plates 104 together and to urge the jaw portions 110 into engagementwith one another.

The jaw portions 110 of the plates 104 are provided with a pair of bondline gripping flanges 122 which are disposed inwardly at substantiallyright angles to adjacent jaw portions of the plates. Each bond linegripping flange 122 and adjacent jaw portion 110 have a generallyL-shaped cross-sectional configuration which is best seen in FIG. 12.When the jaws of the module 20 are in the closed position, as is shownin FIG. 10, the short arms of the L's which correspond to the grippingflanges 122 are substantially colinear. The jaw portions 110 of theplates 104 which correspond to the long arms of the L's are providedwith a plurality of ventilating apertures 124 adjacent the grippingflanges 122 as best seen in FIGS. 11 and 13. The ventilating apertures124 provide passageways for hot air and/or radiant heat from theexternal heat source to reach the laid-together materials clampedbetween a pair of gripping faces 126 on the bond line gripping flanges122. The apertures 124 also allow a craftsman heating clamped materialsto observe their heat recovery as it progresses.

The optimum dimensions and specifications for the clip module 20 justdescribed are, of course a function of the clip's intended use andengineering tradeoffs. Generally, a larger percent ratio of aperturesurface area to total jaw portion surface area is desirable as itfacilitates a more rapid heating and cooling of the clamped materials.This percent ratio is, of course, limited by structural considerations.Preferably, the percent ratio is between about 10% and about 90%. Forthe clip to be easily hand installable, it is preferred that thepressure applied by squeezing the handle portions 112 between thumb andforefinger as shown in FIG. 1 not exceed 10 pounds. More preferably,that the squeezing force required to open the jaws be between about 3pounds and about 5 pounds. The thermal conductivity of the clip ispreferably greater than the thermal conductivity of the material to bebonded. The gripping faces 126 on the bond line gripping flanges 122 arepreferably smooth so as to not cut or otherwise damage the clampedmaterials. The force per unit area exerted on clamped materials dependsin part on the longitudinal length of the clip, shown in FIG. 11 as thedimension "A"; the thickness of the gripping flanges 122, shown in FIG.11 as the dimension "B"; the distance of the gripping flanges from theball-bearing joints, shown in FIG. 12 as the dimension "E"; and theplacement and characteristics of the tubular clamping springs 120. Theclamping force per unit area must be sufficient to hold the materials tobe bonded in intimate contact initially and throughout the heating andcooling cycle. The flange depth, shown as the dimension "D" in FIG. 12is equal to one-half the internal jaw clearance, shown as the dimension"C" in FIG. 10. The internal jaw clearance "C" is preferably equal to orgreater than the composite thickness of the laid-together, bonded andfully recovered materials with which the clip module 20 is to be used.Such a clearance prevents the inside surfaces 106 of the plates 104 frominterfering with the recovery of the clamped materials.

By way of example, a few dimensions and specifications are given for apresently prefered clip module 20 intended for use with a longitudinallyslit section of Raychem type MS-251 self-bonding, heat shrinkable tubingin the formation of a wrap-around closure member such as is shown inFIGS. 1 and 2. The wall thickness of this tubing is initially about0.030 inches and has a fully recovered thickness of about 0.090 inches.This tubing is available from Raychem Corporation, Menlo Park, Calif.The plates 104 are stamped from low carbon steel sheets about 0.040inches thick and chrome plated. The approximate values for thedimensions represented in FIGS. 10, 11 and 12 by the letters A, B, C, D,and E are as follows:

A = 2 inches

B = 0.040 inches

C = 0.180 inches

D = 0.090 inches

E = 1 inch

Each gripping face 126 has a surface area of about 0.08 square inchesand exerts a clamping force of about 40 pounds per square inch. Theapertures 124 are formed with a plurality of mutually parallel slots,each 1/2 inch long × 1/8 inch wide disposed on 1/4 inch centerssubstantially as shown in FIG. 11.

From the foregoing detailed description, it will be evident that thereare a number of changes, adaptations and modifications of the presentinvention which come within the province of those skilled in the art;however, it is intended that all such variations not departing from thespirit of the invention be considered as within the scope thereof aslimited solely by the appended claims.

We claim:
 1. A modular clip assembly for clamping laid-together portionsof cross-linked, dimensionally heat unstable polymeric material along ato-be-formed bond line during the application of heat from an externalheat source to form a bond between clamped portions of said materialcomprising:a first manually operable clip module possessing first andsecond parallel jaws formed with a pair of cooperating plates, each ofsaid cooperating plates possessing a terminal portion disposed inwardlyto form a pair of continuous bond line gripping flanges, each continuousgripping flange and associated plate having a generally L-shapedcross-sectional configuration, the short arms of the L's whichcorrespond to said continuous gripping flanges being substantiallycolinear when said jaws are closed, the portions of said platescorresponding to the long arms of the L's being provided with aplurality of ventilating apertures adjacent said continuous grippingflanges, first and second handles connected respectively to said firstand second jaws, hinge means for allowing said jaws to movecooperatively into and out of engagement with each other inlongitudinally parallel relationship, and spring means for urging saidjaws into mutual engagement; a second manually operable clip modulepossessing elements corresponding to those of said first manuallyoperable clip module; and flexible linking means interconnecting saidfirst and second clip modules for maintaining a selected longitudinalrelationship between said modules thereby facilitating the handinstallation of said modular clip assembly along said to-be-formed bondline.
 2. A modular clip assembly for clamping laid-together portions ofcross-linked, dimensionally heat unstable polymeric material along ato-be-formed bond line during the application of heat from an externalheat source to form a bond between clamped portions of said materialcomprising:a first manually operable clip module possessing first andsecond parallel jaws, first and second handles connected respectively tosaid first and second jaws, hinge means for allowing said jaws to movecooperatively into and out of engagement with each other inlongitudinally parallel relationship, and spring means for urging saidjaws into mutual engagement; and a second manually operable clip modulepossessing elements corresponding to those of said first manuallyoperable clip module, one of said manually operable clip modules beingformed with a pair of substantially identical plates of generallyT-shaped configuration, each plate possessing a jaw portioncorresponding to the upper horizontal part of the T, a handle portioncorresponding to the vertical part of the T and a pair of projections onsaid jaw portion disposed parallel to and on opposite sides of saidhandle portion, said projections being cupped on their inside surfacesto form spherical-bearing seats, said plates being juxtaposed with apair of ball bearings disposed between aligned bearing seats therebyforming two joints about which said plates may rock, said selected clipmodule further possessing a pair of tubular clamping springs whichembrace said joints holding said plates together and urging said jawportions into engagement, said selected clip module further comprisingjaw portions of said plates possessing a pair of continuous bond linegripping flanges disposed inwardly at substantially right angles toadjacent jaw portions of said plates, each continuous bond line grippingflange and adjacent jaw portions of said plate having a generallyL-shaped cross-sectional configuration, the short arm of the Lcorresponding to said continuous flange having a length of at leastone-half maximum composite thickness of fully heat-recovered materialsintended to be clamped by said selected clip module, the portions ofsaid plate corresponding to the long arm of the L being provided with aplurality of ventilating apertures adjacent said continuous flange; andflexible linking means interconnecting said first and second clipmodules for maintaining a selected longitudinal relationship betweensaid modules thereby facilitating the hand installation of said modularclip assembly along said to-be-formed bond line.
 3. The modular clipassembly of claim 2 wherein said flexible linking means comprises acable.
 4. The modular clip assembly of claim 2 wherein said flexiblelinking means comprises a chain.
 5. In a clip of the type having a pairof longitudinally parallel jaws formed with a pair of cooperatingplates, spring means urging said jaws toward a closed position in whichsaid jaws are in contact with each other and manually operable means forurging said jaws away from said closed position the improvmentcomprising:a pair of jaws each possessing a continuous gripping flangedisposed inwardly at the terminal portion of each said cooperatingplate, each continuous gripping flange and associated plate having agenerally L-shaped cross-sectional configuration, the short arm of theL's which correspond to said continuous gripping flanges beingsubstantially colinear in said closed position, the portions of saidplates corresponding to the long arms of the L's being provided with aplurality of ventilating apertures adjacent said continuous grippingflanges.
 6. An improved clip intended for use in a modular longitudinalassembly of similar clips to clamp laid-together portions ofcross-linked, dimensionally heat unstable polymeric material along ato-be-formed bond line during the application of heat from an externalheat source to form a bond between clamped portions of said material,said clip being of the type formed with a pair of substantiallyidentical plates of generally T-shaped configuration, each platepossessing a jaw portion corresponding to the upper horizontal part ofthe T, a handle portion corresponding to the vertical part of the T anda pair of projections on said jaw portion disposed parallel to and onopposite sides of said handle portion, said projections being cupped ontheir inside surfaces to form spherical-bearing seats, said plates beingjuxtaposed with a pair of ball bearings disposed between aligned bearingseats thereby forming two joints about which said plates may rock, saidclip further possessing a pair of tubular clamping springs which embracesaid joints holding said plates together and urging said jaw portionsinto engagement wherein the improvement comprises:jaw portions of saidplates possessing a pair of continuous bond line gripping flangesdisposed inwardly at substantially right angles to adjacent jaw portionsof said plates, each continuous bond line gripping flange and adjacentjaw portion of said plate having a generally L-shaped cross-sectionalconfiguration, the short arm of the L corresponding to said continuousflange having a length of at least one-half the maximum compositethickness of fully heat-recovered materials intended to be clamped bysaid modular clip, the portions of said plate corresponding to the longarm of the L being provided with a plurality of ventilating aperturesadjacent said continuous flange.
 7. A modular clip assembly for clampinglaid-together portions of cross-linked, dimensionally heat unstablepolymeric material along a to-be-formed bond line during the applicationof heat from an external heat source to form a bond between clampedportions of said material comprising:a first manually operable clipmodule possessing first and second parallel jaws, each of said jawspossessing a terminal portion disposed inwardly to form a pair ofcontinuous bond line gripping flanges, each of said continuous grippingflanges and said jaws forming a generally L-shaped cross-sectionalconfiguration, first and second handles connected respectively to saidfirst and second jaws, hinge means for allowing said jaws to movecooperatively into and out of engagement with each other inlongitudinally parallel relationship, and spring means for urging saidjaws into mutual engagement; a second manually operable clip modulepossessing elements corresponding to those of said first manuallyoperable clip module; and flexible linking means interconnecting saidfirst and second clip modules for maintaining a selected longitudinalrelationship between said modules thereby facilitating the handinstallation of said modular clip assembly along said to-be-formed bondline.
 8. The modular clip assembly of claim 7, wherein said continuousgripping flanges corresponding to the short arms of the L-shapedcross-sectional configuration are substantially colinear when said jawsare closed.
 9. The modular clip assembly of claim 7, wherein said firstand second parallel jaws belonging to one of said manually operable clipmodules engage along a common plane forming a straight line therein. 10.The modular clip assembly of claim 7, wherein said first and secondparallel jaws belonging to one of said manually operable clip modulesengage along a common plane forming a curved line therein.
 11. Themodular clip assembly of claim 7, wherein said first and second paralleljaws belonging to one of said manually operable clip modules engagealong a first and second interconnected curved plane.
 12. The modularclip assembly of claim 7, wherein said flexible linking means comprisesa cable.
 13. The modular clip assembly of claim 7, wherein said flexiblelinking means comprises a chain.
 14. The modular clip assembly of claim7, wherein said first and second parallel jaws corresponding to the longarms of the L-shaped cross-sectional configuration being substantiallyshorter in length than the longitudinal length of said terminal grippingflanges corresponding to the short arms of the L-shaped cross-sectionalconfiguration.
 15. The modular clip assembly of claim 7, wherein aselected one of said manually operable clip modules is formed with apair of substantially identical jaws of generally T-shapedconfiguration, each jaw possessing a flange portion corresponding to theupper horizontal part of the T, a handle portion corresponding to aportion of the vertical part of the T, and a pair of projectionsdisposed parallel to and on opposite sides of said handle portion, saidprojections being cupped on their inside surfaces to formspherical-bearing seats, said jaws being juxtaposed with a pair of ballbearings disposed between aligned bearing seats thereby forming twojoints about which said jaws may rock, said selected clip module furtherpossessing a pair of tubular clamping springs which embrace said jointsholding said jaws together and urging said gripping flange intoengagement.
 16. The modular clip assembly of claim 7, wherein said jawsare provided with a plurality of ventilating apertures adjacent to saidcontinuous gripping flanges.